Abstract:

Anthocyanins are a kind of important flavonoids produced during the secondary metabolism of plants.Anthocyanidin synthase(ANS)catalyzes the conversion of leucoanthocyanidins to anthocyanidins in the anthocyanin synthesis pathway.Previous studies have shown that the anthocyanidin synthase gene plays an important role during the coloring process of plant organs.To investigate whether the gene can promote anthocyanin synthesis in potato tubers,using the red-skinned and red-fleshed colored potato variety Hongmei as the material,anthocyanidin synthasegene was isolated from tubers of color potato by RT-PCR, the characterization analyzed by bioinformatics and function validated by overexpression into Arabidopsis thaliana.The results showed that sequence 1 406 bp cDNA of the gene was amplified from the potato,including 1 368 bp open reading frame(ORF).The ORF encoded a deduced protein of 455 amino acids.The gene was named as StANS1a by bioinformatics analysis.GenBank accession number is ON512347.The amino acid sequence analysis revealed that the deduced protein contained a DIOX_N'domain located at 52—166 resides and a 2OG_FeⅡ_Oxy domain located at 215—312 resides.Arabidopsis thaliana plants was transformed with constructs overexpression vector StANS1a.The transcriptional expression of StANS1a in transgenic lines were tested by RT-PCR.The results showed that in the same population,the transcriptional expression of StANS1a showed an increase in different transgenic lines compared with the wild-type(Wt).The anthocyanin content was further analyzed in transgenic lines.Compared to the Wt,the anthocyanin contents of the seven lines(T₁—T₇)were increased from 2.17% to 54.61%. These results strongly demonstrated that overexpression of the StANS1a gene could promote anthocyanin synthesis in transgenic plants.The colored potato StANS1a gene plays an important role in the anthocyanin metabolic pathway.

Key words: Color potato, Anthocyanidin synthase gene, Gene clone, Expression analysis, Anthocyanins